Face-to-Face Positive Restrained Rotating Pipe Flange

ABSTRACT

An annular ductile iron flange of nominal size has a non-threaded inner longitudinal surface defining an inner diameter that exceeds the outer diameter of a corresponding length of hubless ductile iron pipe of nominal thickness. The flange also has a basal surface with both a plurality of evenly spaced bolt holes and an annular counterbore adjacent to the inner longitudinal surface. The counterbore has a longitudinal depth slightly larger than the nominal thickness and a radial depth slightly larger than twice the nominal thickness. The flange is coupled to, and configured to rotate longitudinally around, the length of pipe. The bell end of the pipe is machined to an annular stub configured to recess into the counterbore. A threaded annular ductile-iron flange may be screwed onto the spigot end of the pipe.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §120 as acontinuation-in-part of U.S. patent application Ser. No. 14/137,502,filed Dec. 20, 2013, entitled FACE-TO-FACE POSITIVE RESTRAINED ROTATINGPIPE FLANGE, projected to issue on Jan. 24, 2017 as U.S. Pat. No.9,551,446. Said U.S. patent application Ser. No. 14/137,502 is hereinincorporated by reference in its entirety.

TECHNICAL FIELD

This invention relates to flanges, fittings, and other means of securelyconnecting lengths of pipe for water, wastewater, fire protection, andother applications.

BACKGROUND

A flange may be a cast iron (gray iron or ductile iron) plate of nominalsize, generally annular in shape, designed to connect lengths ofcentrifugally cast gray-iron or ductile-iron pipe of correspondingnominal size. A flange of a given nominal size (generally expressed ininches for North American flanges and pipes) may also have a nominalouter diameter. A length of cast iron pipe of a given nominal size mayhave a nominal outer diameter, a minimum nominal thickness depending onits rated water pressure, and a nominal allowance for casting tolerance.A flange may be incorporated into a length of cast iron pipe. The flangemay also be a separate annular plate coupled to a length of pipe viathreading. Taper pipe threads on the internal surface of the flangecorrespond to threads on the external surface of the pipe. Two lengthsof pipe may be connected by bolting or screwing the correspondingflanges to each other, face to face, through a plurality of bolt holesevenly distributed in a concentric circle around the perimeter of theflange. The exact size and number of bolt holes will depend on thenominal size of the flange. A gasket positioned between the two flanges,also annular in shape and fashioned from rubber or a like material, mayseal the connection.

“Corresponding pipe” and “corresponding flange” refer to the fact thatductile iron flanges of nominal size are standardized to fit ductileiron pipe of the same nominal size. For example, ANSI/AWWAC115/A21.15-11, which is incorporated by reference herein in itsentirety, provides that North American ductile iron pipe of 8-inchnominal size may correspond to a standard flange of 8-inch nominal sizehaving an outer diameter of 13.5 inches and eight evenly spaced circularbolt holes of 7/8-inch diameter.

On a large scale construction project, which may involve multipleflanged connections as pipes are run into buildings, through walls,etc., “two-holing” is standard practice to ensure that any two flangesor flanged pipe spools of a given nominal size are properly aligned. Aflange is properly two-holed when a horizontal centerline connecting thetop two bolt holes lies perpendicular to the vertical centerline of thepipe. Section 4.4.4 of ANSI/AWWA C115/A21.15-11 provides thatmisalignment of corresponding bolt holes of the two flanges should notexceed 0.12 inch measured from like points on bolt holes. Similarly,flange faces should be perpendicular to the pipe centerline andparallel, such that face-to-face dimensions at opposite points on theouter diameter of the flanges do not differ by more than 0.06 inch. Whenflanges are properly aligned, any connecting valves, hydrants, fittings,etc. should fit uniformly.

Problems arise when flanges and pipe spools are improperly two-holed ormisaligned, which may happen for a variety of reasons including but notlimited to misaligned plant walls, improperly poured concrete floors,inaccurate equipment specifications, or simple human error. In responseto an improperly aligned flange, a builder may tear down and rebuild awall, pull up and re-pour a floor, or order a new pipe spool piece. Anyof these courses of action may lead to delayed completion, increasedexpenses, or both. Where an improperly two-holed flange may be onlyslightly misaligned with its companion flange, however, the builder mayforce a connection of the two flanges, bolting them together at animproper angle. A forced connection may appear to resolve the problem oftwo misaligned flanges but only conceals and complicates the problem,leading to increased potential for leaking (and further flange alignmentissues) at multiple pipe joints. Leaks may only be discovered long afterthe building has been completed and the builders have left. Equipmentsuppliers, rather than pipefitters, may be called to account for theseleaks. While several solutions to the problem of improper two-holinghave been developed, these solutions may present new challenges.

SUMMARY

A modified rotating pipe flange, and an apparatus incorporating thesame, is disclosed. An annular ductile iron pipe flange has a smoothinner surface whose inner diameter slightly exceeds the outer diameterof a ductile iron pipe spool of the corresponding nominal size. One faceof the flange may include around its inner surface an annularcounterbore. The flange may be configured to rotate freely around theouter diameter of a corresponding length of pipe.

An apparatus for ameliorating misalignment of flanged connections ofductile-iron pipe comprises a pipe spool piece with a flared bell endand a threaded spigot end. The bell end is machined to an annular pipestub. The modified flange is coupled to the pipe spool piece so that thepipe stub may recess into the annular counterbore, flush with the faceof the modified flange. An internally threaded annular ductile iron pipeflange of the same nominal size is then screwed onto the spigot end ofthe pipe spool piece. The modified flange is configured to rotate freelyaround the pipe spool piece, its lateral movement restrained by theflange on the spigot end, until it is bolted to a connecting flange.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not necessarily restrictive of the invention as claimed. Theaccompanying drawings, which are incorporated in and constitute a partof the specification, illustrate embodiments of the invention andtogether with the general description, serve to explain the principlesof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of the invention may be better understood by thoseskilled in the art by reference to the accompanying figures in which:

FIG. 1A is an illustration of a properly two-holed flange.

FIG. 1B is an illustration of a properly two-holed flange.

FIG. 1C is a front view of a pair of improperly two-holed or misalignedflanges.

FIG. 2A is a prior art cross section of a forced connection of twomisaligned flanges.

FIG. 2B is a prior art cross section of a forced connection of twomisaligned flanges.

FIG. 3 is a prior art diagram of multiple flanged joints andconnections.

FIG. 4A is a prior art illustration of a restrained flange adapter.

FIG. 4B is a prior art illustration of a restrained flange adapter.

FIG. 5A is an illustration of a standard annular flange.

FIG. 5B is an illustration of a modified rotating flange.

FIG. 5C is a side view of a modified rotating flange.

FIG. 6A is a side view of a pipe spool piece.

FIG. 6B is a side view of a modified pipe spool piece.

FIG. 7 is an exploded view of a restrained rotating flange device.

FIG. 8A is a side view of a restrained rotating flange device.

FIG. 8B is a side view of a restrained rotating flange device.

FIG. 8C is a side view of a restrained rotating flange device.

FIG. 9 is a cross section of a pipe joint including a restrainedrotating flange device.

FIG. 10 is an exploded view of a pipe joint including a restrainedrotating flange device;

FIG. 11A is a front view of a modified rotating flange according toembodiments of the inventive concepts disclosed herein;

FIG. 11B is a bottom view of the modified rotating flange of FIG. 11A;

FIG. 11C is a bottom view of an alternative embodiment of the modifiedrotating flange of FIG. 11A; and

FIGS. 11D-11E are front views of the modified rotating flange of FIG.11A.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Features of the present invention in its various embodiments areexemplified by the following descriptions with reference to theaccompanying drawings, which describe the present invention with furtherdetail. These drawings depict only selected embodiments of the presentinvention, and should not be considered to limit its scope in any way.

The present invention is a novel solution to the problems of impropertwo-holing and forced connection of misaligned flanges. FIG. 1A depictsa standard annular flange 100, properly two-holed. Standard flanges andmodified flanges in accordance with an embodiment of the presentinvention may be fashioned from ductile iron and conform tospecifications outlined in ANSI/AWWA C115/A21.15-11 and ANSI/AWWAC150/A21.50-08, the latter of which is herein incorporated by referencein its entirety. Bolt holes 104(a), 104(b), . . . are arranged in aconcentric circle around the perimeter of the face 102 of flange 100.When flange 100 is properly two-holed, the common horizontal centerline110 of the top two bolt holes 104(a) and 104(b) (i.e., the bolt holesnearest the top of flange 100) will lie perpendicular to the verticalcenterline 112 of flange 100. Any further valves, pipes, or otherfittings connected to flange 100 will fit uniformly with flange 100 ifthe corresponding flange is also properly two-holed in this way.

FIG. 1B demonstrates verification of a properly two-holed flange: twopins 116(a), 116(b) may be inserted in bolt holes 104(a), 104(b) andlevel 114 coupled to pins 116(a) and 116(b). The horizontal centerline110 of bolt holes 104(a) and 104(b) lies perpendicular to the verticalcenterline 112 of flange 100. The position of level bubble 118 showsthat level 114 is horizontally aligned, and thus flange 100 is properlytwo-holed.

FIG. 1C depicts a standard flange 100 misaligned with a second flange orflanged pipe (behind flange 100 and thus not shown) that has not beenproperly two-holed. The centerline 110 of bolt holes 104(a) and 104(b)lies perpendicular to vertical centerline 112 of flange 100. Bolt holes104(c) and 104(d) of the rear flange, however, are not aligned with boltholes 104(a) and 104(b), nor are they aligned with vertical centerline112. If two connecting flanges are not properly aligned, a secure pipejoint cannot be guaranteed. Rather than pull down a wall, pull up afloor, or wait for a replacement pipe spool, if the misalignment betweentwo flanges is small enough, the bolts may simply be forced through bothsets of holes.

FIGS. 2A and 2B depict a prior art cross section of a forced connection120 between two misaligned flanged pipe sections 122(a) and 122(b).Annular gasket 124, which may comprise a molded elastomer, rubber,thermoplastic, or other like material, may be positioned between twoflanges to seal a pipe joint. Gasket 124 may include holes correspondingto the bolt holes of corresponding flanges, and may further include oneor more concentric raised rings 126 on the face of the gasket toguarantee the seal to a given working pressure and reduce the bolttorque necessary to secure flanged pipe sections 122(a) and 122(b).Because flanged pipe sections 122(a) and 122(b) are not properlyaligned, however, bolts 128(a) and 128(b) may connect bolt holes 104(a)to 104(f) and 104(e) to 104(d) at an improper angle. A secure sealcannot be guaranteed to the necessary working pressure; bolts 128(a) and128(b) may face increased stress and pipe joint 120 may be more likelyto leak or fail than a properly aligned pipe joint or connection. In theshort term, none of these problem factors may be immediately apparent.

In FIG. 3, flanged pipe section 122(a) of pipe run 132(a) must be runthrough wall 130. Pipe joint 120(a) connects flanged pipe section 122(a)to pipe spool piece 140, which in turn connects at pipe joint 120(b) toflanged pipe section 122(b) and pipe run 132(b). Pipe run 132(b) isdesigned to run parallel to wall 130, and pipe runs 132(c), 132(d) and132(e) branch off from pipe run 132(b) at points along the length ofwall 130. If the two flanges comprising pipe joint 120(a) are misalignedor force connected, the integrity or lifespan of pipe joint 120(a) maybe compromised as shown above. However, if pipe joint 120(a) ismisaligned or force-connected, its misalignment may affect pipe joint120(b) as well; the two flanges at joint 120(b) may themselves requirerealignment or may not run precisely as blueprints intend. Thereforepipe run 132(b) may not be properly aligned with wall 130, and branchingpipe runs 132(c), 132(d), and 132(e) may each develop alignment orleakage issues.

FIGS. 4A and 4B depict prior art solutions to the problem of improperlytwo-holed and misaligned flanges, such as the Uniflange manufactured byFord Meter Box, the MegaFlange manufactured by EBAA Iron, and other likerestrained flange adapters. A flanged joint may be replaced by arestrained pipe joint 132 that connects pipe sections 122(a) and 122(b).A series of radially oriented set screws 134(a), 134(b), . . . securethe restrained pipe joint 132 to pipe 122(b) at points along the outersurface of pipe 122(b). While the problem of improper two-holing may beeliminated by restrained flange adapters of this type, othercomplications may arise. The pipe joint may still be vulnerable toleakage or strain if set screws 134(a), 134(b), . . . are unevenly orimproperly torqued. Furthermore, the outer surface of pipe 122(b) may bevulnerable to point loading or distortion at spots where set screws134(a), 134(b), . . . contact (and exert pressure upon) the outersurface. Similarly, corrosion may result from galvanic reaction ofdissimilar metals, e.g., due to contact between carbon steel set screws134(a), 134(b), . . . and the ductile iron outer surface of pipe 122(b).

FIG. 5A depicts a standard raised-face annular flange 100. Flange 100may be fashioned from gray iron or, preferably, ductile iron. In oneaspect, flange 100 includes a threaded inner surface 108 extendingthrough raised face 106. Bolt holes 104(a), 104(b), . . . are evenlyspaced in a concentric circle around the face 102 of flange 100.

FIG. 5B depicts a modified rotating flange 200 of an embodiment of thepresent invention. In one aspect, modified flange 200 may have anannular shape and a series of bolt holes 204(a), 204(b), . . .concentrically arranged around the perimeter of face 202. In a preferredembodiment of the present invention, modified flange 200 may befashioned from ductile iron. In a further aspect, inner surface 208 ofmodified flange 200 may be unthreaded and may define an inner diameterslightly larger than the outer diameter of the pipe corresponding tomodified flange 200. In a preferred embodiment of the present invention,a length of corresponding pipe may be inserted into the inner diameterof modified flange 200 so that modified flange 200 may rotate freelyaround the longitudinal axis of the pipe. In a further aspect, modifiedflange 200 may include an annular counterbore 206 adjacent to innersurface 208, expanding the inner diameter of modified flange 200 on oneface 202.

FIG. 5C depicts a side view of a modified rotating flange 200 of anembodiment of the present invention. Inner surface 208 of modifiedflange 200 defines an inner diameter slightly larger than that definedby the internal threading of a corresponding standard flange. In oneaspect, annular counterbore 206 expands the inner diameter of modifiedflange 200 on face 202(a). In a preferred embodiment of the presentinvention, annular counterbore 206 has a longitudinal depth (i.e., asmeasured along longitudinal centerline 210 of modified flange 200)approximating the sum of the nominal thickness of the pipe correspondingto modified flange 200 and the nominal allowance for casting toleranceof the pipe, and a radial depth approximating the sum of twice thenominal thickness of the pipe and the nominal allowance for castingtolerance. In a further aspect, bolt holes 204(a) and 204(c) may rotatewith modified flange 200 in order to uniformly fit any correspondingflange, whether or not the bolt holes of the corresponding flange areproperly two-holed.

FIG. 6A depicts a side view of a pipe spool piece 140 corresponding to amodified flange of an embodiment of the present invention. In oneaspect, pipe spool piece 140 may have a nominal thickness 142corresponding to its nominal size, a flared bell end 144, and anexternally threaded spigot end 146. In a preferred embodiment of thepresent invention, pipe spool 140 is fashioned from centrifugally casthubless ductile iron pipe of special thickness class 53. In a furtheraspect, pipe spool 140 may be of any standard length. Alternatively,spigot end 146 may be cut and threaded so that pipe spool 140 may becustomized to any reasonable or desirable length.

FIG. 6B depicts a side view of a modified pipe spool piece 240 inaccordance with an embodiment of the present invention. In one aspect,the flared end of pipe spool 240 may be machined (via lathe, CNC latheor any like device) to remove excess material 248 and produce an annularpipe stub 244. In a preferred embodiment of the present invention, pipestub 244 may have a longitudinal thickness (i.e., measured parallel tolongitudinal centerline 210) approximating the nominal thickness 242 ofpipe spool 240 and a radial thickness twice its longitudinal thickness.

FIG. 7 depicts an exploded view of the assembly of a restrained rotatingflange device 300 of an embodiment of the present invention. In oneaspect, modified pipe spool 240 may have an externally threaded spigotend 246 and an annular pipe stub 244 at its bell end. In a secondaspect, modified rotating flange 200 may be inserted around modifiedpipe spool 240 such that inner surface 208 of modified rotating flange200 may freely rotate around the outer surface of modified pipe spool240 and annular counterbore 206 faces pipe stub 244. In a third aspect,standard annular flange 100 may be inserted around modified pipe spool240 such that internal threads 108 of flange 100 and external threads246 of modified pipe spool 240 both secure flange 100 to modified pipespool 240 and restrict the lateral movement of modified flange 200. In apreferred embodiment of the present invention, standard flange 100 isinserted onto modified pipe spool 240 such that bolt holes 104(a),104(b) of flange 100 are properly two-holed. Consequently, even ifrestrained rotating flange device 300 is connected to an improperlytwo-holed flange at its stub end 244, modified flange 200 may rotate inorder to align with and uniformly fit the improperly two-holed flange.Once modified rotating flange 200 is appropriately rotated and bolted tothe improperly two-holed flange, standard flange 100 may present aproperly two-holed flange for any pipe joint connected to standardflange 100 at spigot end 246.

FIGS. 8A, 8B, and 8C depict a side view of the assembly of a restrainedrotating flange device 300 of an embodiment of the present invention. Ina first aspect, modified rotating flange 200 may be inserted aroundmodified pipe spool 240, such that annular counterbore 206 faces pipestub 244. One skilled in the art will recognize that the dimensions ofannular counterbore 206 may slightly exceed those of pipe stub 244 dueto the allowance for casting tolerance. Consequently, pipe stub 244 mayrecess into annular counterbore 206, and the face 202 of modified flange200 may rest flush with the annular basal surface of pipe stub 244. Inan exemplary embodiment of the present invention, pipe stub 244 mayrecess inside annular counterbore 206 such that an annular gap betweenthe basal surface of pipe stub 244 and the face 202 of modified flange200 corresponds to a concentric ring of an annular gasket sized to fitbetween modified flange 200 and modified pipe spool 240. In a furtheraspect, standard flange 100 is inserted around modified pipe spool 240such that the internal threads 108 of flange 100 couple with theexternal threads 246 of pipe spool 240. In a preferred embodiment of thepresent invention, flange 100 is screwed onto modified pipe spool 240 toa pressure tolerance of 500 psi. Flange 100 may therefore restrict thelateral movement of modified flange 200, preventing modified flange 200from falling off pipe spool 240 before bolting to a connecting flange.In a still further aspect, depicted in FIG. 8C, flange 100 may berotated so as to rest flush with the spigot end 246 of pipe spool 240,or a length of pipe spool 240 projecting beyond flange 100 may beremoved.

FIG. 9 depicts a cross section of a pipe joint 220 including arestrained rotating flange device 300 of an embodiment of the presentinvention. Bolts 128(a), 128(b) connect flange device 300 to flangedpipe 122 through bolt holes 204(a), 204(c) in modified rotating flange200. As bolt holes 204(a), 204(b) in modified flange 200 align with boltholes 104(c), 104(f) in flanged pipe 122, bolts 128(a), 128(b) are alsoperfectly aligned, and a stable, sealed pipe joint connection isprovided. Gasket 124 is positioned between flange device 300 and flangedpipe 122 to secure the seal. In a preferred embodiment of the presentinvention, an annular gap between pipe stub 244 and annular counterbore206 corresponds to concentric raised ring 126 of gasket 124.

FIG. 10 depicts an exploded view of a pipe joint 220 including arestrained rotating flange device 300 of an embodiment of the presentinvention. As pipe stub 244 of flange device 300 is brought into placeto connect with flanged pipe 122, modified flange 200 may be rotated sothat bolt holes 204(a), 204(b), . . . align precisely with bolt holes104(a), 104(b), . . . in flanged pipe 122. Bolts 128(a), 128(b), . . .may then connect bolt holes 204(a), 204(b), . . . of modified flange200, bolt holes 104(g), 104(h), . . . in annular gasket 124, and boltholes 104(a), 104(b), . . . of flanged pipe 122, providing a sealed andstable pipe joint connection. In a preferred embodiment of the presentinvention, an annular gap between pipe stub 244 and the face of modifiedflange 200 corresponds to concentric raised ring 126 of annular gasket124.

Referring generally to FIGS. 11A-E, the modified rotating flange 200 amay be implemented and may function similarly to the modified rotatingflange 200 of FIG. 5B, except that the modified rotating flange 200 amay comprise a left flange piece 200 b and a right flange piece 200 c.The left flange piece 200 b and right flange piece 200 c may have asubstantially semicircular basal surface, the two semicircular basalsurface combining to form the basal surface, or face 202, of themodified rotating flange 200 a. The left flange piece 200 b and rightflange piece 200 c may be connected by a hinge 212 installed around, orin place of, the bolt hole 204 a. The modified rotating flange 200 a maythus be installed, for example, around the modified pipe spool 240 ofFIG. 8B, even if a threaded flange 100 has been attached to the modifiedpipe spool 240.

Referring in particular to FIGS. 11B and 11C, the section of themodified rotating flange 200 a where the left flange piece 200 b and theright flange piece 200 c may be characterized by a front portion 202 aand a rear portion 202 b. For example, when the left flange piece 200 band the right flange piece 200 c are secured via the bolt hole 204 c,the front portion 202 a may rest flush with the rear portion 202 b andforward of the rear portion 202 b, relative to the front basal surface(front face 202) of the modified rotating flange 200 a; the bolt hole204 c may be configured to align the front portion 202 a and the rearportion 202 b. It should be noted that the position of the front basalsurface (front face 202) of the modified rotating flange 200 a, and thusthe relationship between the front portion 202 a and the rear portion202 b, may be aligned with the annular counterbore 206, as shown by FIG.11B, or opposite the annular counterbore, as shown by FIG. 11C.

Referring in particular to FIGS. 11D and 11E, the modified rotatingflange 100 a may be installed around the modified pipe spool 240 (see,e.g., FIG. 8B) by rotating the left flange piece 200 b and right flangepiece 200 c around the hinge 212, expanding (214) and contracting (216)the modified rotating flange 100 a to fit around the outer diameter ofthe modified pipe spool (as shown by FIG. 11D in particular), andconnecting the left flange piece 200 b and right flange piece 200 c (viafront portion 202 a and rear portion 202 b) to each other via the bolthole 204 c opposite the bolt hole 204 a. The installed modified rotatingflange 100 a may then slide freely parallel to the longitudinalcenterline of the modified pipe spool 240 (see, e.g., FIG. 8A), as theinner surface 208 slightly exceeds the outer diameter of the modifiedpipe spool 240.

Those having skill in the art will appreciate that there are variousvehicles by which processes and/or systems and/or other technologiesdescribed herein can be effected (e.g., hardware, software, and/orfirmware), and that the preferred vehicle will vary with the context inwhich the processes and/or systems and/or other technologies aredeployed. For example, if an implementer determines that speed andaccuracy are paramount, the implementer may opt for a mainly hardwareand/or firmware vehicle; alternatively, if flexibility is paramount, theimplementer may opt for a mainly software implementation; or, yet againalternatively, the implementer may opt for some combination of hardware,software, and/or firmware. Hence, there are several possible vehicles bywhich the processes and/or devices and/or other technologies describedherein may be effected, none of which is inherently superior to theother in that any vehicle to be utilized is a choice dependent upon thecontext in which the vehicle will be deployed and the specific concerns(e.g., speed, flexibility, or predictability) of the implementer, any ofwhich may vary. Those skilled in the art will recognize that opticalaspects of implementations will typically employ optically-orientedhardware, software, and or firmware.

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures aremerely exemplary, and that in fact many other architectures can beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “connected”, or “coupled”, toeach other to achieve the desired functionality, and any two componentscapable of being so associated can also be viewed as being “couplable”,to each other to achieve the desired functionality. Specific examples ofcouplable include but are not limited to physically mateable and/orphysically interacting components and/or wirelessly interactable and/orwirelessly interacting components and/or logically interacting and/orlogically interactable components.

While particular aspects of the present subject matter described hereinhave been shown and described, it will be apparent to those skilled inthe art that, based upon the teachings herein, changes and modificationsmay be made without departing from the subject matter described hereinand its broader aspects and, therefore, the appended claims are toencompass within their scope all such changes and modifications as arewithin the true spirit and scope of the subject matter described herein.

I claim:
 1. An annular ductile iron flange of nominal size, comprising an outer longitudinal surface, a non-threaded inner longitudinal surface, at least one basal surface, and a plurality of bolt holes evenly spaced around the at least one basal surface, wherein the improvement comprises: the inner longitudinal surface defining an inner diameter exceeding an outer diameter of a centrifugally cast length of hubless ductile iron pipe of said nominal size, the pipe having a nominal thickness and a nominal casting allowance, the flange configured to rotate longitudinally around the pipe; the at least one basal surface including a first basal surface having an annular counterbore adjacent to said inner longitudinal surface, the counterbore having a longitudinal depth equivalent to the sum of the nominal thickness and the nominal casting allowance and a radial depth equivalent to between 1.5 and 2.5 times the sum of the nominal thickness and the nominal casting allowance; and the flange comprising a first flange segment and a second flange segment, the first flange segment and the second flange segment of semicircular shape and hingedly connected, the first flange segment and the second flange segment sharing at least one bolt hole of the plurality of bolt holes.
 2. An annular flange of ductile iron having a nominal size, comprising: an outer longitudinal surface; an inner longitudinal surface defining a first inner diameter exceeding an outer diameter corresponding to a length of pipe of ductile iron having at least the nominal size, a nominal thickness and a nominal casting allowance; at least one basal surface, the at least one basal surface including: an annular counterbore adjacent to the inner longitudinal surface, the annular counterbore having a longitudinal depth equivalent to the sum of the nominal thickness and the nominal casting allowance and a radial depth equivalent to between 1.5 and 2.5 times the sum of the nominal thickness and the nominal casting allowance; and a plurality of bolt holes evenly spaced in the at least one basal surface; the annular flange comprising a first flange segment and a second flange segment, the first flange segment and the second flange segment of semicircular shape and hingedly connected, the first flange segment and the second flange segment sharing at least one bolt hole of the plurality of bolt holes.
 3. The flange of claim 4, wherein the annular counterbore has a radial depth equivalent to the twice the sum of the nominal thickness and the nominal casting allowance.
 4. A connector for ameliorating misalignment of flange connected ductile-iron pipes, comprising: a length of hubless ductile-iron pipe having at least a nominal size, a nominal thickness, and a nominal casting allowance, said pipe having a flared bell end, an externally threaded spigot end, and an outer diameter; a first annular flange of ductile iron having the nominal size and comprising: a first outer longitudinal surface; a first inner longitudinal surface configured to be threadedly connected to the spigot end; at least one first basal surface; and a plurality of first bolt holes evenly spaced in the at least one first basal surface; a second annular flange of ductile iron having the nominal size and configured to rotate longitudinally around the pipe, the second annular flange comprising: a second outer longitudinal surface; a second inner longitudinal surface defining an inner diameter exceeding the outer diameter of the pipe; at least one second basal surface, the at least one second basal surface including a third basal surface having an annular counterbore adjacent to the second inner longitudinal surface, the counterbore having a longitudinal depth equivalent to the sum of the nominal thickness and the nominal casting allowance and a radial depth equivalent to between 1.5 and 2.5 times the sum of the nominal thickness and the nominal casting allowance; and a plurality of second bolt holes evenly spaced in the at least one second basal surface; the second annular flange comprising a first flange segment and a second flange segment, the first flange segment and the second flange segment of semicircular shape and hingedly connected, the first flange segment and the second flange segment sharing at least one second bolt hole; the bell end of the pipe machined to an annular pipe stub configured to recess into the annular counterbore, the pipe stub having a longitudinal thickness equivalent to the nominal thickness and a radial thickness equivalent to between 1.5 and 2.5 times the nominal thickness.
 5. The connector of claim 4, wherein: the radial depth of the counterbore is equivalent to twice the sum of the nominal thickness and the casting allowance; and the radial thickness of the pipe stub is equivalent to twice the nominal thickness. 